Intergroup bias, although it unfairly benefits some, has negative personal and social consequences for all citizens. The consequences of racism, for example, include more than the unrealized potential of members of minority groups and the failure to capitalize on diversity. Direct costs to majority as well as to minority groups involve the loss of human and financial resources as the result of unemployment, poverty, crime, drugs, ill-health, and personal, social and family dysfunction (see Crain & Weisman, 1972; Bowser & Hunt, 1981; Jones, 1986; McLoyd, 1990). The proposed research develops and examines the Common Ingroup Identity Model for reducing intergroup bias and conflict. This model focuses on mediating cognitive processes and asserts that (1) more harmonious, intergroup interactions can be facilitated by factors that transform members' cognitive representations of the memberships from two groups to one group; (2) favorable generalization to outgroup members not specifically involved in the contact situation will be maximized when the salience of the initial group identities are maintained, but within the context of a common ingroup identity. Thus the proposed research examines how the recognition of diversity could lead to reduced bias when groups differ in important and enduring ways. The proposal derives a set of testable hypotheses and proposes a series of ten studies that together address several portions of the overarching theoretical framework. Some studies consider factors that are proposed to induce a common ingroup identity (e.g, elements of intergroup cooperation, equal status between groups, positive mood and linguistic factors). Additional studies examine proposed consequences of a common ingroup identity (e.g., cooperation, self-disclosure and altruism). Finally, two studies apply principles derived from the model to reducing interracial bias.